S. Rajeswari

Structural and electrochemical behaviour of sol-gel zirconia films on 316L stainless-steel in simulated body fluid environment

Abstract Sol-gel thin film offers a number of advantages that makes it an attractive method for obtaining ceramic coatings on metallic implants. In this study, the feasibility of using a polymeric sol-gel zirconia film on 316L SS substrate was evaluated using potentiodynamic polarization measurements to measure the corrosion resistance in simulated body fluid environment. Fairly uniform, dense and crack-free films were produced by dip-coating the 316L stainless-steel substrate in a precursor solution containing sonocatalysed zirconium propoxide and yttrium acetate, followed by firing at 600 °C in vacuum. The resultant films were characterized by thermal studies (TGA-DTA), XRD, FT-IR and polarization studies.

Hydroxyapatite coatings on sulfuric acid treated type 316L SS and its electrochemical behaviour in Ringer's solution

Abstract The corrosion behaviour of various concentrations of sulfuric acid immersion on 316L SS is studied using cyclic anodic polarisation experiments. The results from the experiments showed that 20% sulfuric acid treated stainless steels showed better withstanding to pitting attack compared to the pristine 316L SS. Similarly, the hydroxyapatite (HAP) coatings carried on 20% H2SO4 treated 316L SS exhibited excellent resistance to localized attack towards the HAP coatings on pristine 316L SS.

Effect of inhibitors and biocide on corrosion control of mild steel in natural aqueous environment

Abstract A triazole phosphonate compounds, namely, 3-benzyledene amino 1,2,4-triazole phosphonate (BATP), 3-cinnamyledene amino 1,2,4-triazole phosphonate (CATP) and 3-anisalidene amino1, 2,4-triazole phosphonate (AATP), were synthesized and its inhibition efficiency along with biocide action on corrosion of mild steel in natural aqueous solution was investigated through weight loss and electrochemical polarization techniques. Results from experimental observation have indicated AATP as a better corrosion inhibitor for mild steel in aqueous solution. Additionally, the formulation consisting of AATP, Mo and CTAB offered good corrosion inhibition efficiency. Surface characterization studies were carried out to establish the mechanism of corrosion inhibition of mild steel in aqueous media.

Synthesis of hydroxyapatite on silica gel surface by using glycerin as a drying control chemical additive

Abstract Synthetic hydroxyapatite (HAP) was grown on surface of silica gels by immersing silica monoliths in a simulated body fluid at room temperature (37 °C). The gels were prepared by the sol-gel method and the drying process was controlled by using different organic additives (mono- and diethylene glycol, formamide and glycerin) to obtain large monoliths. Ca/P molar ratios were estimated, X-ray diffraction (XRD) and Fourier transform-infrared spectroscopy (FT-IR) were performed to determine the phase analysis and functional group composition, respectively. Further, the surface morphology of the silica gels was studied by scanning electron microscopy (SEM). The formation of HAP competes with the formation of crystalline calcium carbonate, but the results indicate optimisation of conditions for the growth of the former as a function of the type and concentration of the additive.